I'm trying to understand the closest_point function in qgis. For that, I created a polygon layer with two features, and through the Geometry Generator I intend to find the closest point between those two.

This is the expression I'm using, but it is not working:

closest_point(geometry (get_feature_by_id('closest', 1)), geometry(get_feature_by_id ('closest', 2)))

Can someone help me to find out why?

enter image description here

  • How is it not working? Please explain what you expect and what happens instead. Mar 20, 2021 at 16:35
  • Well, I'm really a beginner in this but I guess it was supposed to draw the point in geometry one closest to geometry two, isn't that right? And that doesn't happen.
    – Felippe M.
    Mar 20, 2021 at 16:50

1 Answer 1


Your expression should work well, but you have geometry errors in your layer: you have multipart geometries with just one part. That's what the Check Geometries tool found.

To solve the problem: run Menu Vector / Geometry tools / Multipart to singleparts - in the resulting layer, both your original as well as the following expression should work:

    geometry (get_feature_by_id (@layer, 1)), 
    geometry (get_feature_by_id (@layer, 2))

@layer refers to the current layer.

enter image description here

  • I'm really really sorry. I shared it wrongly. This is the right link: drive.google.com/drive/folders/…
    – Felippe M.
    Mar 20, 2021 at 17:26
  • How did you identify that it was a multipart? I can only say a feature is a multipart when you try to select it and and both features are selected.
    – Felippe M.
    Mar 20, 2021 at 17:44
  • 1
    I used the Check Geometries tool. It was the inverse: you had two separate features, but somehow QGIS consiedered them to be multipart, but they consisted both of just one part, thus it was inconsistent.
    – Babel
    Mar 20, 2021 at 17:46
  • Go figure! Well thank you very much, it worked perfectly!!
    – Felippe M.
    Mar 20, 2021 at 17:48

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